MK3 7MGE Emissions Problem

Bru · 04-16-2015, 02:34 PM

It could be a bad plug connection. They get corroded too. Also they get pushed back in the plastic holder where they don't make contact. They are supposed to pinch against the prongs on the sensor. You could rig up a test harness with connectors that grip the prongs on the sensor (without touching each other and shorting) to bridge to the plug to see if the code goes away after clearing it first. There is also a test procedure using a Volt meter to probe the back of the plug at the ECU which is located behind the glove box.

Here is a link to the test procedure.
http://www.cygnusx1.net/Supra/Librar...aspx?S=FI&P=41

The plug back layout.
http://www.cygnusx1.net/Supra/Librar...aspx?S=FI&P=31

The voltage between THW and E2 should be O.1 to 1.0 Volts with the engine warmed up and the ignition switch in the on position (not running).

Here is a test of the sensor itself.
http://www.cygnusx1.net/Supra/Librar...spx?S=FI&P=113

Getting those square plugs with the spring clips off with out damaging them is always a chore.
I use a pointy tip to pull the clip away on each side and carefully wiggle it loose. They snap on a lot easier with the clip back in its groove.

04-16-2015, 02:34 PM	#6
Bru Bone Stock w Upgrades ;-) Join Date: Apr 2010 Location: Tampa Bay Posts: 210	It could be a bad plug connection. They get corroded too. Also they get pushed back in the plastic holder where they don't make contact. They are supposed to pinch against the prongs on the sensor. You could rig up a test harness with connectors that grip the prongs on the sensor (without touching each other and shorting) to bridge to the plug to see if the code goes away after clearing it first. There is also a test procedure using a Volt meter to probe the back of the plug at the ECU which is located behind the glove box. Here is a link to the test procedure. http://www.cygnusx1.net/Supra/Librar...aspx?S=FI&P=41 The plug back layout. http://www.cygnusx1.net/Supra/Librar...aspx?S=FI&P=31 The voltage between THW and E2 should be O.1 to 1.0 Volts with the engine warmed up and the ignition switch in the on position (not running). Here is a test of the sensor itself. http://www.cygnusx1.net/Supra/Librar...spx?S=FI&P=113 Getting those square plugs with the spring clips off with out damaging them is always a chore. I use a pointy tip to pull the clip away on each side and carefully wiggle it loose. They snap on a lot easier with the clip back in its groove. Last edited by Bru; 04-22-2015 at 12:47 PM.